CHARACTERS.
Dull brown mixed with black, under parts bluish-gray; ears, of moderate
size, nearly hidden by the fur; tail, a little longer than the head.
SYNONYME.
ARVICOLA RIPARIUS ? Ord.
BANK MEADOW-MOUSE. Richardson, F. B. A., p. 120.
DESCRIPTION.
Head, rather large; incisors, large, much exposed, and projecting beyond
the nose--upper, flattened anteriorly, marked with scarcely perceptible
perpendicular grooves, and with a somewhat irregular and rather oblique cutting
edge--lower, twice as long as the upper, and narrower, slightly curved, and
rounded anteriorly; nose, thick and obtuse; whiskers, few and rather short;
eyes, rather small; ears, ovate, rounded at the tip, not easily distinguishable
until the surrounding fur is blown or moved aside.
Body, more slender behind than at the shoulders, the hind-legs not being so
far apart as the fore-legs; tail, rather short, tapering, and thinly covered
with short hairs; fore-legs, short; feet, rather small, with four slender, well
separated toes, and the rudiment of a thumb, which is armed with a minute nail;
claws, small, compressed, and pointed; the third toe nearly equals the middle
one, which is the longest.
The hair of the toes projects over the claws but does not conceal them; the
toes of the hind-feet are longer than those of the fore-feet, and their claws
are somewhat longer; the inner one is the shortest, the second longer than the
third, and the third longer than the fourth; the first and fifth are
considerably shorter than the others, and are placed farther back.
The fur on the back is about eight lines long, but not so soft and fine as
in some other animals of the genus; it is nearly as long on the crown and
cheeks, but is shorter and thinner on the chest and belly.
COLOUR.
Incisors, yellow; claws, white; whiskers, black; the whole dorsal aspect,
including the shoulders and outsides of the thighs, is dull or dusky brown,
proceeding from an intimate mixture of yellowish-brown and black, which colours
are confined to the tips of the hairs and are so mingled as to produce a nearly
uniform shade of colour without lustre.
From the roots to near the tips, the fur has a uniform shining
blackish-gray colour; on the ventral aspect (lower parts) it is bluish-gray; the
margin of the upper lip, the chin, and the feet, are dull white; tail, dark
brown above, lighter beneath, the two colours meeting by an even line.
DIMENSIONS.
Length of head and body, . . . . . . . . 7 inches.
Length of tail, . . . . . . . . . . . 2 inches.
HABITS.
DRUMMOND, who procured this Meadow-Mouse, states that its habits are
analogous to those of the common water-rat of Europe (Arvicola amphibius), with
which it may be easily confounded, although the shortness of its tail may serve
as a mark by which to distinguish it.
It frequents moist meadows amongst the Rocky Mountains, and swims and dives
well, taking to the water at once when pursued. All Meadow-Mice indeed are
capital swimmers. We some time since amused ourselves watching one that had
fallen into a circular cistern partly built up with stone and partly excavated
out of the solid rock by blasting, and which was plastered with cement on the
inside to make it water-tight. This cistern had about four feet of water in it.
On one side there was a projecting rounded knob of stone some five or six inches
long and about two wide, which slanted out of the water so that the upper edge
of it was dry. Upon this little resting-place there was a large Arvicola
Pennsylvanica (Wilson's Meadow-Mouse) seated very quietly, having probably
tumbled in the preceding night. When we approached the edge and looked down
into the clear element we at first did not observe the Rat, but as soon as we
espied him he saw us, immediately dived, and swam around underneath the surface;
quite rapidly; he soon arose, however, and regained his position on the ledge,
and we determined to save him from what had been his impending fate--drowning or
starving, or both. We procured a plank, and gently lowering one end of it
towards the ledge, thought he would take advantage of the inclined plane thus
afforded him, to come out; but in our awkwardness we suffered the plank to slip,
and at the plash in the water the little fellow dived and swam around several
times before he again returned to his resting place, where we now had the end of
the board fixed, so that he could get upon it. As soon as he was on it, we
began to raise the plank, but when we had him about three feet above the surface
he dashed off into the water, making as pretty a dive as need be. He always
looked quite dry, and not a hair of his coat was soiled or turned during these
frequent immersions, and it was quite interesting to see the inquisitive looks
he cast towards us, turning his head and appearing to have strong doubts whether
we meant to help, or to make an end of him. We put down the plank again, and
after two attempts, in both of which his timidity induced him to jump off it
when he was nearly at the edge of the cistern, he at last reached the top, and
in a moment disappeared amid the weeds and grasses around.
GEOGRAPHICAL DISTRIBUTION.
The only information we possess of the habitat of this animal is from
DRUMMOND, who states that he captured it near the foot of the Rocky Mountains.
GENERAL REMARKS.
This species possesses longer and stronger incisors than any other American
Rat of this genus; its mouth presenting in fact a miniature resemblance to that
of the musk-rat.
Although the Arvicola xanthognatha is a larger animal than the present, yet
its incisors are not more than half as long as in this species.
We have named this Arvicola in honour of Sir JOHN RICHARDSON, who in
describing it (Fauna Boreali Americana, p. 120), applied to it, with a doubt,
the name of Arvicola riparius, ORD, from which it differs so much as to render a
comparison here unnecessary.